In recent years, low-carb diets have become more popular as people search for ways to lose weight. Some people argue that following a low-carb diet helps with weight and blood sugar control better than a diet that emphasizes carbohydrate-rich foods. Research looking at whether low-carb diets have benefits over higher carb ones are hard to interpret as it depends on the composition of the carbohydrates a person eats. Ultra-processed carbs have a different effect on metabolic health and body weight than fiber-rich carbs, including fruits and vegetables.
Low-carb diets contain substantial quantities of protein, the most satiating macronutrient. That comes in handy when you’re trying to shed extra pounds. Plus, the protein helps preserve muscle while you’re losing body fat. Low-carb diets are also high in fat, which slows digestion and helps people feel fuller. Studies show that protein suppresses appetite hormones and may reduce calorie consumption because of its appetite-suppressing benefits. Ever notice how you feel fuller after a bowl of cottage cheese than a bag of chips? However, a diet that contains healthy carbohydrates contains more fiber, another satiating dietary component. Fiber slows the movement of food through the digestive tract, and that helps reign in hunger.
The Battle of the Weight Loss Diets
By now you might wonder which dietary approach is best for controlling hunger? A study looked at this issue. For the study, researchers recruited 84 individuals with type 2 diabetes. The participants were all overweight or obese and they assigned each to one of two low-calorie diets, low-carb or high-carb. Both diets contained a similar number of calories, 30% below the calories required for maintenance. The composition of the low-carb diet was such that only 14% of calories came from carbs while the other was 53% carbs. The individuals also took part in a structured exercise program 3 days per week.
Participants in the study followed their respective diets for 2 years while researchers quantified their levels of hunger using visual charts and questionnaires. The results? Both groups lost a similar amount of weight over the 2-year study, irrespective of which diet they ate. Success! However, the dieters had differing levels of hunger. You sometimes hear that low-carb diets curb hunger more, but that’s not what this study found. The subjects who ate the high-carb diet felt fuller and more satisfied than the low-carbers.
Why does hunger matter, especially if both groups lost weight? Think about what happens after you reach your ideal body weight. You’ll have an easier time sticking to an eating plan and maintaining the weight you lose if you don’t feel hungry. Research shows that over 80% of people who lose 10% or more of their body weight gain it all back and often more. So, weight loss maintenance is a challenge even if you lose the weight. If you can control hunger, you’re one step ahead of the game.
Should You Restrict an Entire Macronutrient?
Another disadvantage of adopting a low-carb diet is that it reduces an entire macronutrient, carbohydrates. Such diets are hard to stick with longer term. Plus, with this degree of carbohydrate restriction, you enter nutritional ketosis where your body makes ketone bodies from fatty acids. Although ketone bodies can serve as an alternative source of energy, it’s not clear what the long-term effects of being in nutritional ketosis. It’s not clear what the effects of forcing your body to survive on ketones and the breakdown of stored fat are. Many people don’t feel their best when they start a very low-carb diet as the body adapts to burning fat over carbohydrates. During this time, you may experience flu-like symptoms, fatigue, and headaches. Once your body adapts to burning mostly fat, you feel better but the effects can linger in some people.
One reason people continue to recommend low-carb diets is they can lead to fast weight loss. In fact, you may lose weight faster on a low-carb diet, but some of the weight loss is water weight and stored glycogen loss. Stored glycogen holds on to water and once you deplete your glycogen stores, you lose body water too and the number on the scale drops. However, this isn’t true of fat loss. If you exercise intensely, a very, low-carb diet can reduce your performance. That’s because muscle cells use carbohydrates as their principal energy source during intense exercise. During low to moderate-intensity exercise you may feel fine and not experience a drop in performance. It’s when you launch into a workout where vigorous workout that it’s harder to perform on a very low-carb diet.
The Bottom Line
As compelling as they may sound, avoid fad diets and eating plans that decimate an important macronutrient like carbohydrates. It’s better for your health and waistline longer term if you eat in a manner you can sustain for years to come, not just to lose weight short term. Will you enjoy consuming a diet that contains only 14% of calories from carbs for the years to come? And how will it affect your exercise performance? As the study shows, you may have less hunger if you consume a moderate carbohydrate diet and include lots of fiber-rich fruits, vegetables, legumes, and whole grains in your diet. These are nutrient-dense foods that also help you feel more satisfied between meals and that will help maintain the weight you lose.
Make sure you’re getting enough dietary protein too. Studies show that protein is the most satiating macronutrient and when you combine it with fiber, you have a winning combination. So, choose more plant-based sources of protein so you get protein and fiber. The best approach to eating is one that supplies you with the most nutrients and leaves you feeling satisfied.
- Struik NA, Brinkworth GD, Thompson CH, et al. Very low and higher carbohydrate diets promote differential appetite responses in adults with type 2 diabetes: a randomized trial. J Nutr. doi: 10.1093/jn/nxz344.
- Am J Clin Nutr. 2015 Jun;101(6):1320S-1329S. Epub 2015 Apr 29.
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